Wind power is considered one of the cleanest, most environmentally friendly energy sources presently available, and wind turbines have gained increased attention in this regard. A modern wind turbine typically includes a tower, a generator, a gearbox, a nacelle, and one or more rotor blades. The rotor blades capture kinetic energy from wind using known airfoil principles and transmit the kinetic energy through rotational energy to turn a shaft coupling the rotor blades to a gearbox, or if a gearbox is not used, directly to the generator. The generator then converts the mechanical energy to electrical energy that may be deployed to a utility grid.
To properly orient the nacelle and the rotor blades relative to the direction of the wind, wind turbines typically include one or more yaw and/or pitch bearings. The yaw and/or pitch bearings are typically slewing bearings which are rotational roller-element bearings that typically support a heavy but slow-turning or slow-oscillating load. As such, yaw bearings permit rotation of the nacelle and are mounted between the tower and the nacelle, whereas pitch bearings permit rotation of the rotor blades and are mounted between the rotatable hub and one of the rotor blades. Typical yaw and/or pitch bearings include an outer and inner race with a plurality of roller elements (e.g. ball bearings) configured between the races.
More specifically, four-point slewing ring bearings have ball plugs that can be removed such that the roller elements can be easily inserted between the races. Currently, one or more taper pins are used in conventional balls plug to help maintain the radial seating of the plug. For example, one or more taper pins may be inserted through the ball plug(s), i.e. in a direction generally perpendicular to a longitudinal axis of the ball plug(s). At times, the taper pin(s) can cause areas of increased stress concentration.
Accordingly, the art is continuously seeking new and improved systems and methods for ball plug retention for a slewing ring bearing (such as a pitch or yaw bearing of a wind turbine).